As a hearing aid engineer (and one of 8.5 million users) I'm particularly interested in zinc-air technology, specifically with humidity. One engineer I know calls it a fuel cell, but nstead of pumping in O2 it extracts it out of the air.
Batteries may have existed 1000 or more year before Volta: see Wikipedia's History of the Battery. If this was the case, it's hard to see why such a useful technology disappeared for so long. Perhaps it was banned by religious forces claiming it was the work of the devil -- or a scientific threat to religion. More likely there was a huge patent dispute which completely halted the Progress of Science and useful Arts :-)
@Caleb....I'm sure there's lots of tech like this, but just consider Peltier effect - discovered in the 1830's, but only in widespread used these days for coolers etc (and rings, as you recently pointed out, though as you also pointed out this is the complimentary Seebeck effect (ie generating electricity form a temperature difference, rather than Peltier which is generating a temperature difference form a current?))
Useful for what to whome? That was the midevil period though so anything "strange" might have branded you a witch.. without Generators to charge batteries you couldn't do much - and we didn't have generators until 1873, but wow things cascaded quickly once we had power generation.
I am very interested in this subject and wish today's products would be made compatible with rechargable lithium cells running at 3.7v and normal alkalines at 1.5v so we could start having AAA, AA, 9V (3.7x3), etc pure lithium cells. I know it might be somewhat tricky, but it would be nice to get rid of heavy, single use, low power density alkaline land fille batteries for good. With the speed we replace electronics these day's it wouldn't take long.
This is mainly for non-rechargables (acctually it could apply to rechargable too). Is there a standard load voltage drop vs load that's used to indicate the internal battery resistance is to high for practical use ? Digital cameras tend to be very picky about power supply. I've taken digitial camera batteries deemed BAD by the camera and used them succesfully in other less picky electronics. ( I wouldn't suggest using them in a pace maker). This begs the question: Are we discarding nearly good batteries ? Maybe recycling usefull batteries or worse sending them to the land fill.
Also, Nickel Cadmium types were notorious for growing metal-fiber 'wires', that would partially short out a cell. There appeared a capacitor-based rejuvenator that would pulse a high-current into the cell to blow out the metal fibers and breathe new life. A similar treatment was touted to break loose sulfation in lead-acid cells. The applied voltage waveform shape and duration was critical to keep from doing too much damage. In some cases, it killed the remaining life, but was sometimes worth the risk.
@Ivan...I use a lot of NiCds and actually made up a "rejuvenator" for them to zap them with a high current for a short time, discharge, then zap again. I did this with a 555 and entered it for the 555 competition a couple of years ago, the circuit is here:
Mixed success, some batteries can't be fixed, but on some it works a treat. You need to put a battery on the rejvenator for an hour or two, then give it a full charge at the normal rate. I have specified 2C zap (ie a current of twice the AH capacity of the battery) but you can go to 5C or more for stubborn ones.
I just use a high current supply (eg a PC Power supply) but you can also use a capacitor to give the "zap". I prefer a high current supply as it gives a more sustained and controllable zap.
@eetcowie: "Also, Nickel Cadmium types were notorious for growing metal-fiber 'wires', that would partially short out a cell. There appeared a capacitor-based rejuvenator that would pulse a high-current into the cell to blow out the metal fibers and breathe new life."
Back in the mid-to-late 70s Popular Electronics had a simple circuit for a NiCd zapper. It had a 24V transformer and a full-wave bridge that charged a capacitor, and it had a selector switch (charge or zap), a pushbutton to zap, and a meter to monitor the charge on the cap and on the battery. A friend built one to try to resurrect some surplus NiCds he'd bought. One let out a tremendous FLASH and a ZAP, and then started to take a charge. The article said if it didn't start taking a charge after 2 or 3 zaps it never would. He was able to recover most of the "dead" batteries. Not much of a special waveform, but at the cost of used batteries, you didn't lose much by trying. I doubt that would work for Li cells!
I also read that another failure mode with NiCds was that a weak cell caught in a string of good cells would be charged in reverse.
Crusty1: There are many 'rejuvinator' devices that are used here in the states for large truck batteries. If you can get an extra couple of months usage out of a battery it is worth the 8-10 hours that the process takes.
@Rgarvin640:Yes we used to manually use the lab power pack to step up the current to a dead NiCad untill the voltage started to drop and then discharge with a short, some times it would blow the short.
I have a lot of tales about battery use in London Underground Trains and before they were sold off Bus batteries.
I love the single cell lead acid batteries we used on the battery locomotives used to maintain track. They were very big 3 foot high an 1 foot deep float charged from the track 660 V DC during the day.
Pulse charging, became popular after Nickel Cadmium came out, to measure the internal resistance. It did something like what you describe, but also had the advantage to help break loose (spoken loosely) materials from the electrodes (or in the case of NiCd to help prevent the formation of micro-fine shorts).
Ivan: Some where in your articles it would be helpfull to discuss the shipping issues with different battery chemistryies. This is something that can catch both designers and PM's off guard, at least the first time they go thru it. :)
Ivan, although nuclear RTGs are not for mainstream applications, I hope you will incldue them in your discussion, for the benefit of we space junkies. I have read that the old standby Pu-238 is not the optimum choice for deep space vehicle RTGs and I'm curious about the pros & cons of different radioactive isotopes for RTG use.
I also find it fascinating that even after more than 36 years in space, the 487 watt (at launch) batteries on Voyager 1 are still producing about 250 watts.
Thanks for selecting battery as a subject.I have been desining battery chargers in industry( Lead Acid) since 1972 for Indian Railways and Post and Telegraph Department. What I learned is they can use the LA batteries for more than 10 years. They used singal cell units with every day maintainence. However what I heard for my car battery themaximum life as per the auto repairer is one to three years as per usage of the car. Sulphatation, high starting current demand non tubular design and mobile use (Sunjected to acceleration in all direction) being the main problem.
I also heared about polymer conductor battery that has long life (may be now being used ih cell phones) But is there any varient in capacities comparable to lead acid batteries?
Keep in mind a Pb-based battery needs to be kept fully charged or it dies, so it is derated to allow for capacity loss over the expected life of a battery. And in some countries you need to crank at very low temperature where you have only say 25% capacity available. In temperate climates you can get away with a much smaller battery, especially when you consider you do not have to keep the battery fully charged. It is commonly stated you need only half the capacity of a Pb-based battery. Shipping of Li is an issue, however if each cell is less than 20Wh then it is not that hard.
What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.